Cervical dysplasia is the abnormal growth of cells on the surface of the cervix. Although this is not cancer, it is considered a precancerous condition.

Cervical dysplasia is grouped into three categories:

• CIN I -- mild dysplasia (only the lower one-third of cells in the upper layer of the cervix are abnormal)
• CIN II -- moderate to marked dysplasia (up to two-thirds of the layer contains abnormal cells)
• CIN III -- severe dysplasia to carcinoma in situ (precancerous cells are in the entire top layer of the cervix)

Cervical intraepithelial neoplasia (CIN); Precancerous changes of the cervix

Most cases of cervical dysplasia occur in women aged 25 to 35, although it can develop at any age.

While all causes of cervical dysplasia are not known, most cases of cervical cancer and severe dyplasia are caused by infection of the cervix with a persistent, high-risk strain of human papilloma virus (HPV).

The following may increase your risk of cervical dysplasia:

• Becoming sexually active before age 18
• Giving birth before age 16
• If your mother took a drug called diethylstilbestrol (DES) during pregnancy
• Multiple sexual partners
• Other illnesses or medications that suppress your immune system
• Persistent, high-risk HPV (genital warts) infection of the cervix
• Smoking

ACOG Practice Bulletin No. 99: management of abnormal cervical cytology and histology. Obstet Gynecol. 2008;112(6):1419-1444.

Committee on Adolescent Health Care: ACOG Working Group on Immunization. ACOG Committee Opinion No. 344: Human papillomavirus vaccination. Obstet Gynecol. 2006;108:699-705.

Noller KL. Intraepithelial neoplasia of the lower genital tract (cervix, vulva): etiology, screening, diagnostic techniques, management. In: Katz VL, Lentz GM, Lobo RA, Gershenson DM. Comprehensive Gynecology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2007:chap. 28.

Wright TC Jr, Massad LS, Dunton CJ, et al. American Society for Colposcopy and Cervical Pathology-sponsored Consensus Conference: 2006 consensus guidelines for the management of women with cervical intraepithelial neoplasia or adenocarcihnoma in situ. Am J Obstet Gynecol. 2007;197(4):340-345.

Wright TC Jr, Massad LS, Dunton CJ, et al. American Society for Colposcopy and Cervical Pathology-sponsored Consensus Conference: 2006 consensus guidelines for the management of women with abnormal cervical cancer screening tests. Am J Obstet Gynecol. 2007;197(4):346-355.